// The MIT License (MIT)
//
// Copyright (c) 2017 - present zqqf16
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

import Foundation

protocol MdfindWrapperDelegate: class {
    func mdfindWrapper(_ wrapper: MdfindWrapper, didFindResult result: [NSMetadataItem]?)
}

class MdfindWrapper {
    let query = NSMetadataQuery()
    weak var delegate: MdfindWrapperDelegate?
    
    init() {
        let nc = NotificationCenter.default
        nc.addObserver(self, selector: #selector(handleResult(_:)), name: .NSMetadataQueryDidFinishGathering, object: nil)
        nc.addObserver(self, selector: #selector(handleResult(_:)), name: .NSMetadataQueryDidUpdate, object: nil)
    }
    
    deinit {
        NotificationCenter.default.removeObserver(self)
    }
    
    func start(withCondition condition: String) {
        self.stop()
        
        self.query.predicate = NSPredicate(fromMetadataQueryString: condition)
        self.query.start()
    }
    
    func stop() {
        self.query.stop()
    }
    
    @objc func handleResult(_ notification: NSNotification) {
        if let query = notification.object as? NSMetadataQuery, query == self.query {
            self.delegate?.mdfindWrapper(self, didFindResult: query.results as? [NSMetadataItem])
        }
    }
}
